The present invention relates to signal level adjustment apparatus and control methods therefor which are suitable for use in production of video/audio content, as well as computer programs related to such signal level adjustment. For example, the present invention concerns a mixer, video switcher or the like for processing audio signals and/or video signals.
For production of video/audio content, it is necessary to manipulate a great number of devices, such as a plurality of video tape recorders for reproducing video/audio signals as video/audio materials (i.e., material video/audio signals) or recording finished or completed content, a digital mixer for mixing audio signals and a video switcher for switching between video signals. Because it is very troublesome for a human operator to individually operate these devices, there has been known a technique that uses a control apparatus for remote-controlling the various devices in a centralized manner. Namely, with this known technique, the human operator can operate the various devices by mainly manipulating the control apparatus alone, so that the human operator can appropriately carry on the content production as desired.
When switching between material audio signals of two channels is to be made, a crossfade process is generally performed for fading-in the audio signal of one of the channels while fading-out the audio signal of the other channel. The above-mentioned control apparatus can also instruct a digital mixer to perform the crossfade process. Namely, once the human operator performs predetermined operation on the control apparatus, a command instructing a cross-face process (i.e., crossfade execution instruction) is transmitted from the control apparatus to the digital mixer. Upon receipt of the crossfade-instructing command, the digital mixer carries out the instructed crossfade process on the basis of prestored crossfade setting information. Namely, audio signals of a group of input channels are faded out while audio signals of another group of input channels are faded in. During that time, faders corresponding to the various channels are automatically driven in an upward/downward direction on an operation panel of the digital mixer. Such a digital mixer that can be remote-controlled from outside is disclosed, for example, in “DM2000 Instruction Manual”, published by Yamaha Corporation in February, 2002.
However, when a crossfade has been instructed from the control apparatus, the above-discussed technique can not cease the crossfade only for a certain one or ones of the channels via the operation panel of the digital mixer. Further, when the human operator desires to cease the crossfade for only a certain one or ones of the channels, he or she may, in some cases, want the corresponding faders to be restored to their respective states or positions before execution of the crossfade, or, in other cases, want the corresponding faders to be stopped at desired positions after the start of the crossfade execution. In addition, it has not been possible for the user to ascertain, near the faders, the channels to be faded in and to be faded out in the crossfade process.